1. Field of the Invention
The invention relates to semiconductor wafer process systems and, more particularly, the invention relates to a method and apparatus for controlling contamination in a loadlock of a semiconductor wafer processing system.
2. Description of the Background Art
Semiconductor wafer processing systems comprise a loadlock wherein a plurality of wafers are stacked that are awaiting processing within a system. These wafers are removed from the loadlock one at a time by a robot and transported to various processing chambers within the system. Once processed, the wafers are returned from the process chambers to the wafer cassette in the loadlock for removal from the system.
During wafer processing within the system contaminants adsorb onto the wafers. Typically the reactant gases adsorb onto the wafer surface and when the wafer is returned to the loadlock the adsorbed material will desorb. The desorbed gases combine with moisture in the loadlock to form a corrosive film that coats the interior surfaces of the loadlock and the wafers. Such coating of the interior surfaces causes corrosion of the surfaces within the loadlock, and causes the formation of condensation particles upon the wafers. The surface corrosion creates tremendous quantities of corrosion byproduct particulates that disperse throughout the loadlock to contaminate the wafers.
Therefore, a need exists in the art for a method and apparatus that controls corrosive contaminants within a loadlock.